1. Field of the Invention
The present invention relates to oil well pumps and more particularly to an improved hydraulic oil well pump that is electronically controlled using limit or proximity switches to control a valving arrangement that eliminates shock or excess load from the pumping string or sucker rod during pumping, and especially when changing direction of the sucker rod at the bottom of a stroke.
2. General Background of the Invention
Several patents have issued that relate generally to the pumping of oil from an oil well. Examples of those patents are contained in the following table, wherein the order of listing has no significance other than chronological.
TABLEISSUE DATEPAT. NO.TITLEMM-DD-YY4,503,752Hydraulic Pumping UnitMar. 12, 19854,761,120Well Pumping Unit and Control SystemAug. 2, 19885,143,153Rotary Oil Well Pump and Sucker RodSep. 1, 1992Lift5,390,743Installation and Method for the OffshoreFeb. 21, 1995Exploitation of Small Fields6,394,461Pressure Compensated Stuffing Box forMay 28, 2002Reciprocating Pumping Units2003/0085036Combination Well Kick Off and GasMay 8, 2003Lift Booster Unit6,595,280Submersible Well Pumping System withJul. 22, 2003an Improved Hydraulically ActuatedSwitching Mechanism2005/0155758Well Tubing/Casing Vibrator ApparatusJul. 21, 2005